Corrugated acoustic ducts are commonly used in the air handling systems of automobiles. Such corrugated ducts are formed of a series of undulations creating a spiral pattern much like the thread on a fastener. A corrugation is comprised of multiple undulations, and an undulation consists of one full ridge and one full groove which lie parallel to one another. This structure can clearly be seen in FIG. 1, which depicts a corrugated acoustic duct 10 having a series of undulations 12 defined by alternating ridges and 14 and grooves 16. The undulations are disposed at a helical angle ED. For example, a Sonoflex™ acoustic duct is manufactured by West Akron, 571 Kennedy Rd., Akron, Ohio.
Unfortunately, such corrugated acoustic ducts are manufactured with a number of undulations that varies for a set distance D along the length of the tube. Thus, the thread pattern also varies, and the size of each ridge or groove may also vary within certain tolerances. Accordingly, the automotive industry has traditionally connected cylindrical plastic tubing to the acoustic tubing through the use of adhesives, staples, rivets, clamps, plastic over-molding processes, or a combination of the above. While these traditional retention features accommodate the variance in the undulations and thread pattern, they result in additional materials, specialized equipment and tools for connection and installation, increased labor and higher cost in order to make a successful connection which does not allow water through.
Accordingly, there exists a need to provide a retention feature for connecting a plastic tube to a corrugated acoustic duct which accommodates the variance in undulations and thread pattern, while minimizing the materials, specialized equipment and tools, labor and cost of making a successful connection.